public class Combinatorial{
    public static void main(String[] args){
        for(String arg: args){

        }
	Calculate cal = new Calculate();
        int [] arr = new int [args.length];
        for(int i=0; i<args.length; i++) {
            arr[i] = Integer.parseInt(args[i]);
        }
	int result = cal.com(arr[0],arr[1]);
	System.out.println("C("+arr[0]+","+arr[1]+")="+result);
    }
}
class Calculate {

    int com(int a,int b) {
        if (a == b || b == 0) {
            return 1;
        } else {
            return com(a - 1, b - 1) + com(a - 1, b);
        }
    }
}

